Developments in lightwave technology continue today at a rapid pace. Such advances have improved the system performance and reduced cost of fiber optic cables and associated optoelectronic equipment, which carry information over hair-thin strands of glass instead of conventional metallic media. Consequently, because of these considerations and additional performance advantages as well, fiber optic cable has supplanted copper wire as the preferred transmission medium in many telecommunications applications.
Initially, fiber optic cable was installed only in long-distance, intercity networks and interoffice trunks. Today, however, such cable is being placed in the local loop feeder network. Future applications will extend fiber optic cable for distribution to the customer premises itself In fact, a proliferation of new information services is now available, or is being proposed for the office and home by local telephone companies and cable TV companies, to take advantage of the high communication capacity that fiber optic cable offers. Such interactive services include, for example, local area networks (LANs), educational/entertainment video, energy management, alarm monitoring and home banking.
Relief of congested transmission facilities and demand for the above-identified information services will require placement of new fiber optic facilities, especially aerial cable installations in less populated areas, where such facilities are geographically dispersed, where terrain or construction conditions dictate, or where other economic reasons dictate.
Notwithstanding the advantages of fiber optic cable and increased demand, there are still drawbacks to universally using fiber optic cable instead of conventional metallic media. First, fiber optic cable is more fragile than copper wire or coaxial cable. In addition, fiber optic cable is more sensitive to pulling, bending and crushing forces. Accordingly, fiber optic cable demands more stringent installation and maintenance techniques than those media. If the cable is otherwise mishandled, portions of the cable have to be replaced because broken, crushed or kinked cables result in degraded transmission performance. The time and expense and inconvenience to customers associated with replacing or relocating aerially-installed fiber optic cable is substantial. This is due to high manpower requirements and the use of expensive equipment needed to install, test and maintain such transmission facilities. Those skilled in the art have not yet addressed the need to reduce the costs and inefficiencies associated with such activity after initial installation of fiber optic cable is completed.
As is well known, for the purpose of maintenance and service, there are advantages for aerially storing an extra length of cable in a fiber optic transmission line. The extra length of cable is commonly stored by looping it around the outer periphery of an aerial device which is hung from a support messenger strand for the fiber optic line, or, alternatively, mounted on a transmission line pole. In a known device, a generally U-shaped channel, constituting the outer periphery of the aerial device, forms a guide for the cable along the sides and the return arc portion of the device. In this arrangement, a workman bends a strand of cable around the outside periphery of the device to put it into storage.
Typically, the most important fiber optic cable parameter is its bending radius. When a fiber optic cable is being installed, and when it is finally in place, the cable must not be bent less than the minimum cable bending radius specified by the manufacturer. Of course, there are many types of fiber optic cable having different bending radii. So the issue becomes trying to accommodate the different bending radii when aerially installing different fiber optic cable. The type of known device mentioned above is a one piece device having a fixed bend diameter, therefore can only accommodate a limited number of bend radii of fiber optic cable. Thus, different sized devices must be available and utilized in the field.
It is, therefore, an object of the present invention to provide an adjustable fiber optic strand storage unit and method in the industry that will eliminate the need for different sized units to accommodate different bending radii of a variety of fiber optic cable.
Another object of the present invention to provide an adjustable fiber optic strand storage unit and method in the industry that will inexpensively support and maintain an extra length of fiber optic cable slack in an aerial installation.
Still, another object of the present invention is to provide such a storage unit that is adjustable to accommodate a variety of different bending radii of an assortment of fiber optic cable.
A further object of the present invention is to provide an aerial storage unit of the type described, which can be readily molded or formed, and which preferably minimizes or eliminates electrical hazards to workmen when handling the storage unit near electrical transmission lines and other electrical problems such as lightning.